Nat Phys 2008, 4:859–863.CrossRef 23. Sato Y, Tanaka Y, Upham J, Takahashi Y, Asano T, Noda S: Strong coupling between distant photonic nanocavities and its dynamic control. Nat Photon 2012, 6:56–61.CrossRef 24. Vučković J, Lončar M, Mabuchi H, Scherer A: Design of photonic crystal microcavities for cavity QED. Phys Rev E 2001, 65:016608.CrossRef 25. Akahane Y, Asano T, Song B-S, Noda S: High-Q photonic nanocavity in a two-dimensional photonic crystal. Nature 2003, 425:944–947.CrossRef 26. Akahane Y, Asano T, Song B-S, Noda S: Fine-tuned high-Q photonic-crystal nanocavity. Selleckchem Ilomastat Opt Express 2005, 13:1202–1214.CrossRef
27. Song B-S, Noda S, Asano T, Akahane Y: Ultra-high-Q photonic double-heterostructure nanocavity. Nat Mater 2005, 4:207–210.CrossRef 28. Hagino H, Takahashi Y, Tanaka Y, Asano T, Noda S: Effects of fluctuation in air hole radii and positions on optical characteristics in photonic crystal heterostructure nanocavities. Phys Rev B 2009, 79:085112.CrossRef 29. Painter O, Lee RK, Scherer A, Yariv A, O’Brien JD, Dapkus PD, Kim I: Two-dimensional photonic band-gap defect mode laser. Temsirolimus in vitro Science 1999, 284:1819–1821.CrossRef
30. Sprik R, Tiggelen BA, Lagendijk A: Optical emission in periodic dielectrics. Europhysics Letters 1996, 35:265.CrossRef 31. Scully MO, Zubairy MS: Quantum Optics. Cambridge: Cambridge University Press; 1997.CrossRef 32. Taflove A, Hagness S: Computational Electrodynamics: The Finite-Difference Time-Domain Method. 3rd edition. Norwood: Artech House; 2005. Competing interests The authors declare that they have no competing interests. Authors’ contributions GC proposed the method for the mode volume, performed the numerical simulations, interpreted the simulation results, and drafted the manuscript. J-FL anticipated the derivation of equations and the interpretation of numerical results. HJ anticipated the coding of the numerical programs. X-LZ and Y-CY anticipated the numerical simulations and the interpretation of numerical results. CJ and X-HW conceived the study, proposed the slab thickness tuning approach, and revised the manuscript
substantially. PAK6 All authors read and approved the final manuscript.”
“Background TiO2 is the most widely used photocatalyst for effective decomposition of organic compounds in air and water under irradiation of UV light with a shorter wavelength, corresponding to its bandgap energy, due to its relatively high photocatalytic activity, biological and chemical stability, low cost, nontoxic nature, and long-term stability. However, the photocatalytic activity of TiO2 (the bandgap of anatase TiO2 is 3.2 eV which can be excited by photons with wavelengths below 387 nm) is limited to irradiation wavelengths in the UV region [1, 2]. However, only about 3% to 5% of the solar spectrum falls in this UV range. This limits the efficient utilization of solar energy for TiO2.